scholarly journals Comparing the Electrochemical Performance ofLiFePO4/C Modified by Mg Doping and MgO Coating

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Jianjun Song ◽  
Ying Zhang ◽  
Guangjie Shao
Keyword(s):  
Electrochemical Performance ◽  
Discharge Capacity ◽  
Retention Rate ◽  
Active Material ◽  
Specific Capacity ◽  
Rate Capability ◽  
Oxide Coating ◽  
Mg Doping ◽  
Battery Material ◽  
Mg Doped

Supervalent cation doping and metal oxide coating are the most efficacious and popular methods to optimize the property of LiFePO4lithium battery material. Mg-doped and MgO-coated LiFePO4/C were synthesized to analyze their individual influence on the electrochemical performance of active material. The specific capacity and rate capability of LiFePO4/C are improved by both MgO coating and Mg doping, especially the Mg-doped sample—Li0.985Mg0.015FePO4/C, whose discharge capacity is up to 163 mAh g−1, 145.5 mAh g−1, 128.3 mAh g−1, and 103.7 mAh g−1at 1 C, 2 C, 5 C, and 10 C, respectively. The cyclic life of electrode is obviously increased by MgO surface modification, and the discharge capacity retention rate of sample LiFePO4/C-MgO2.5is up to 104.2% after 100 cycles. Comparing samples modified by these two methods, Mg doping is more prominent on prompting the capacity and rate capability of LiFePO4, while MgO coating is superior in terms of improving cyclic performance.

scholarly journals Sucrose-Assisted Synthesis of Layered Lithium-Rich Oxide Li[Li0.2Mn0.56Ni0.16Co0.08]O2 as a Cathode of Lithium-Ion Battery

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 436 ◽  
Author(s):  
Song ◽  
Huang ◽  
Zhong
Keyword(s):  
Electrochemical Performance ◽  
Layered Structure ◽  
Retention Rate ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cyclic Stability ◽  
Capacity Retention ◽  
Significant Performance ◽  
Rich Material

：Herein, the lithium-rich material Li[Li0.2Mn0.56Ni0.16Co0.08]O2 is successfully prepared by a sucrose-assisted gel method. With the assistance of sucrose, Li[Li0.2Mn0.56Ni0.16Co0.08]O2 precursors can be uniformly dispersed into sticky sucrose gel without aggregation. XRD shows that the lithium-rich material Li[Li0.2Mn0.56Ni0.16Co0.08]O2 has a well-organized layered structure. The electrochemical performance is influenced by calcination temperature. The results show that the sample Li[Li0.2Mn0.56Ni0.16Co0.08]O2 calcined at 900 °C possess significant performance. This sample delivers higher discharge specific capacity of 252 mAh g−1; rate capability with a capacity retention of 86% when tested at 5C; and excellent cyclic stability with a capacity retention rate of 81% after 100 cycles under 1C test. The sucrose-assisted method shows great potential in fabricating layered lithium-rich materials

scholarly journals Effects of Mg doping on the remarkably enhanced electrochemical performance of Na3V2(PO4)3 cathode materials for sodium ion batteries

2015 ◽  
Vol 3 (18) ◽  
pp. 9578-9586 ◽  
Author(s):  
Hui Li ◽  
Xiqian Yu ◽  
Ying Bai ◽  
Feng Wu ◽  
Chuan Wu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Electronic Conductivity ◽  
Rate Capability ◽  
Sodium Ion ◽  
High Rate ◽  
Cycle Performance ◽  
Sodium Ion Batteries ◽  
Mg Doping ◽  
Enhanced Electrochemical Performance ◽  
Mg Doped

Mg doped Na3V2(PO4)3/C displays better electrochemical performance, especially at a high rate. Enhanced rate capability and cycle performance can be attributed to the optimized particle size, structural stability and enhanced ionic and electronic conductivity induced by Mg doping.

Constructing zigzag-like hollow mesoporous nanospheres MoO2/C with superior lithium storage performance

2021 ◽  
Author(s):  
Wencai Zhao ◽  
Y.F. Yuan ◽  
S.M. Yin ◽  
Gaoshen Cai ◽  
S.Y. Guo
Keyword(s):  
Reaction Kinetics ◽  
Discharge Capacity ◽  
Amorphous Carbon ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Structure Design ◽  
Structure Stability ◽  
Lithium Storage

Abstract Hollow mesoporous nanospheres MoO2/C are successfully constructed through metal chelating reaction between molybdenum acetylacetone and glycerol as well as the Kirkendall effect induced by diammonium hydrogen phosphate. MoO2 nanoparticles coupled by amorphous carbon are assembled to unique zigzag-like hollow mesoporous nanosphere with large specific surface area of 147.7 m2 g-1 and main pore size of 8.7 nm. The content of carbon is 9.1%. As anode material for lithium-ion batteries, the composite shows high specific capacity and excellent cycling performance. At 0.2 A g-1, average discharge capacity stabilizes at 1092 mAh g-1. At 1 A g-1 after 700 cycles, the discharge capacity still reaches 512 mAh g-1. Impressively, the composite preserves intact after 700 cycles. Even at 5 A g-1, the discharge capacity can reach 321 mAh g-1, exhibiting superior rate capability. Various kinetics analyses demonstrate that in electrochemical reaction, the proportion of the surface capacitive effect is higher, and the composite has relatively high diffusion coefficient of Li ions and fast faradic reaction kinetics. Excellent lithium storge performance is attributed to the synergistic effect of zigzag-like hollow mesoporous nanosphere and amorphous carbon, which improves reaction kinetics, structure stability and electronic conductivity of MoO2. The present work provides a new useful structure design strategy for advanced energy storage application of MoO2.

A Facile One-Pot Stepwise Hydrothermal Method for the Synthesis of 3D MoS2/RGO Composites with Improved Lithium Storage Properties

NANO ◽  
2019 ◽  
Vol 14 (03) ◽  
pp. 1950037 ◽  
Author(s):  
Bingning Wang ◽  
Xuehua Liu ◽  
Binghui Xu ◽  
Yanhui Li ◽  
Dan Xiu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Performance ◽  
Hydrothermal Method ◽  
Hydrothermal Treatment ◽  
Active Material ◽  
Rate Capability ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Lithium Storage ◽  
One Pot

Three-dimensional reduced graphene oxide (RGO) matrix decorated with nanoflowers of layered MoS2 (denoted as 3D MoS2/RGO) have been synthesized via a facile one-pot stepwise hydrothermal method. Graphene oxide (GO) is used as precursor of RGO and a 3D GO network is formed in the first-step of hydrothermal treatment. At the second stage of hydrothermal treatment, nanoflowers of layered MoS2 form and anchor on the surface of previously formed 3D RGO network. In this preparation, thiourea not only induces the formation of the 3D architecture at a relatively low temperature, but also works as sulfur precursor of MoS2. The synthesized composites have been investigated with XRD, SEM, TEM, Raman spectra, TGA, N2 sorption technique and electrochemical measurements. In comparison with normal MoS2/RGO composites, the 3D MoS2/RGO composite shows improved electrochemical performance as anode material for lithium-ion batteries. A high reversible capacity of 930[Formula: see text]mAh[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] after 130 cycles under a current density of 200[Formula: see text]mA[Formula: see text][Formula: see text][Formula: see text]g[Formula: see text] as well as good rate capability and superior cyclic stability have been observed. The superior electrochemical performance of the 3D MoS2/RGO composite as anode active material for lithium-ion battery is ascribed to its robust 3D structures, enhanced surface area and the synergistic effect between graphene matrix and the MoS2 nanoflowers subunit.

Investigating the Influence of Different Coating Surface Densities of Electrodes on Electrochemical Performance of Lithium-Ion Batteries

2019 ◽  
Vol 17 (3) ◽  
Author(s):  
Yanping Dang ◽  
Wangyu Liu ◽  
Weigui Xie ◽  
Weiping Qiu
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Surface Density ◽  
Active Material ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Aluminum Foil ◽  
Coating Surface ◽  
Allowable Range ◽  
Polypropylene Separator

Abstract The anode and cathode pieces are vital components of lithium-ion batteries. The coating surface density of active material is a significant parameter involved during the fabrication of electrodes and has considerable impact on battery performance. In this paper, anode and cathode pieces are prepared with different surface densities within the allowable range. The anode and cathode pieces are first graded respectively and then matched up according to different surface density ranges. Afterward, the electrodes are assembled with commercial polypropylene separator in 18,650 cell case and infused with electrolyte. The cathode is constituted with a mixture of nickel cobalt manganese (NCM) ternary material and lithium manganese oxide coated on aluminum foil, while the anode is composed of graphite coated on copper foil. The electrochemical performance and safety properties were tested to investigate the influence of the coating surface density of electrodes and optimize the electrochemical performance by regulating the matching surface density of electrodes. The results indicate that larger surface density of both cathode and anode can provide better battery consistency, while smaller surface density can contribute to better specific capacity and smaller capacity loss after cycling. Modest cost and superior properties can be achieved for lithium-ion batteries by reasonably matching the surface density of anodes and cathodes pieces.

scholarly journals Nanohollow Carbon for Rechargeable Batteries: Ongoing Progresses and Challenges

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiangmin Jiang ◽  
Guangdi Nie ◽  
Ping Nie ◽  
Zhiwei Li ◽  
Zhenghui Pan ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Carbon Nanostructures ◽  
Active Sites ◽  
Electrode Materials ◽  
Mechanical Stability ◽  
High Surface ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Rechargeable Batteries

AbstractAmong the various morphologies of carbon-based materials, hollow carbon nanostructures are of particular interest for energy storage. They have been widely investigated as electrode materials in different types of rechargeable batteries, owing to their high surface areas in association with the high surface-to-volume ratios, controllable pores and pore size distribution, high electrical conductivity, and excellent chemical and mechanical stability, which are beneficial for providing active sites, accelerating electrons/ions transfer, interacting with electrolytes, and giving rise to high specific capacity, rate capability, cycling ability, and overall electrochemical performance. In this overview, we look into the ongoing progresses that are being made with the nanohollow carbon materials, including nanospheres, nanopolyhedrons, and nanofibers, in relation to their applications in the main types of rechargeable batteries. The design and synthesis strategies for them and their electrochemical performance in rechargeable batteries, including lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, and lithium–sulfur batteries are comprehensively reviewed and discussed, together with the challenges being faced and perspectives for them.

scholarly journals Directly Anodized Sulfur-Doped TiO2 Nanotubes as Improved Anodes for Li-ion Batteries

Batteries ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 51
Author(s):  
Davood Sabaghi ◽  
Mahmoud Madian ◽  
Ahmad Omar ◽  
Steffen Oswald ◽  
Margitta Uhlemann ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Discharge Capacity ◽  
Tio2 Nanotubes ◽  
Rate Capability ◽  
Pure Tio2 ◽  
Electrochemical Anodization ◽  
Li Ion Batteries ◽  
Doped Tio2 ◽  
Li Ion ◽  
Elemental Doping

TiO2 represents one of the promising anode materials for lithium ion batteries due to its high thermal and chemical stability, relatively high theoretical specific capacity and low cost. However, the electrochemical performance, particularly for mesoporous TiO2, is limited and must be further developed. Elemental doping is a viable route to enhance rate capability and discharge capacity of TiO2 anodes in Li-ion batteries. Usually, elemental doping requires elevated temperatures, which represents a challenge, particularly for sulfur as a dopant. In this work, S-doped TiO2 nanotubes were successfully synthesized in situ during the electrochemical anodization of a titanium substrate at room temperature. The electrochemical anodization bath represented an ethylene glycol-based solution containing NH4F along with Na2S2O5 as the sulfur source. The S-doped TiO2 anodes demonstrated a higher areal discharge capacity of 95 µAh·cm−2 at a current rate of 100 µA·cm−2 after 100 cycles, as compared to the pure TiO2 nanotubes (60 µAh·cm−2). S-TiO2 also exhibited a significantly improved rate capability up to 2500 µA·cm−2 as compared to undoped TiO2. The improved electrochemical performance, as compared to pure TiO2 nanotubes, is attributed to a lower impedance in S-doped TiO2 nanotubes (STNTs). Thus, the direct S-doping during the anodization process is a promising and cost-effective route towards improved TiO2 anodes for Li-ion batteries.

Improvement of Electrochemical Performance and Thermal Stability by Reducing Residual Lithium Hydroxide on LiNi0.8Co0.1Mn0.1O2 Active Material using Amorphous Carbon Coating

2018 ◽  
Vol 21 (2) ◽  
pp. 071-075 ◽  
Author(s):  
Ji-Woong Shin ◽  
Jong-Tae Son
Keyword(s):  
Thermal Stability ◽  
Electrochemical Performance ◽  
Cathode Material ◽  
Amorphous Carbon ◽  
Carbon Coating ◽  
Solid Electrolyte Interphase ◽  
Active Material ◽  
Rate Capability ◽  
Lithium Carbonate ◽  
Lithium Hydroxide

Using LiNi0.8Co0.1Mn0.1O2 as a starting material, a surface-modified cathode material was obtained by coating it with a nanolayer of amorphous carbon, where the added C12H22O11 (sugar) was transformed to Li2CO3 compounds after reacting with residual LiOH on the surface. A thin and uniformly smooth nanolayer (35 nm thick) was observed on the surface of the LiNi0.8Co0.1Mn0.1O2, as confirmed by transmission electron microscopy (TEM). The amount of residual lithium hydroxide (LiOH) was significantly reduced through the formation of lithium carbonate (Li2CO3). As a result, carbon-coated LiNi0.8Co0.1Mn0.1O2 exhibited noticeable improvement in capacity and rate capability and much lower exothermic heat in the charged state at 4.3V. The improved electrochemical performance and thermal stability are attributed to the carbon coating, which reduced the residual lithium hydroxide, protected the cathode material from reacting with the electrolyte, and slowing the incrassation of the solid electrolyte interphase (SEI) film on the surfaces of the oxide particles.C12H22O11 + 12O2 → 12CO2 + 11H2OPACS number: 73.20.At

scholarly journals Boosting the Rate and Cycling Performance of β-LixV2O5 Nanorods for Li Ion Battery by Electrode Surface Decoration

2019 ◽  
Author(s):  
Panpan Wang ◽  
Yue Du ◽  
Baoyou Zhang ◽  
Yanxin Yao ◽  
Yuchen Xiao ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Electronic Conductivity ◽  
Specific Capacity ◽  
Rate Capability ◽  
Lithium Ion ◽  
Ex Situ ◽  
Practical Application ◽  
Surface Decoration

The <i>β-</i>phase lithium vanadium oxide bronze (<i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub>) with high theoretic specific capacity up to 440 mAh g<sup>-1</sup> is considered as promising cathode materials, however, their practical application is hindered by its poor ionic and electronic conductivity, resulting in unsatisfied cyclic stability and rate capability. Herein, we report the surface decoration of <i>β-</i>Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> cathode using both reduced oxide graphene and ionic conductor LaPO<sub>4</sub>, which significantly promotes the electronic transfer and Li<sup>+</sup> diffusion rate, respectively. As a result, the rGO/LaPO<sub>4</sub>/Li<i><sub>x</sub></i>V<sub>2</sub>O<sub>5</sub> composite exhibits excellent electrochemical performance in terms of high reversible specific capacity of 275.7 mAh g<sup>-1</sup> with high capacity retention of 84.1% after 100 cycles at a current density of 60 mA g<sup>-1</sup>, and acceptable specific capacity of 170.3 mAh g<sup>-1</sup> at high current density of 400 mA g<sup>-1</sup>. The cycled electrode is also analyzed by electrochemical impedance spectroscopy, <i>ex-situ </i>X-ray diffraction and scanning electron microscope, providing further insights into the improvement of electrochemical performance. Our results provide an effective approach to boost the electrochemical properties of lithium vanadates for practical application in lithium ion batteries.

scholarly journals The Role of Silicon in Silicon-Graphite Composite Electrodes Regarding Specific Capacity, Cycle Stability, and Expansion

2021 ◽  
Author(s):  
Erfan Moyassari ◽  
Thomas Roth ◽  
Simon Kücher ◽  
C. C. Chang ◽  
Shang-Chieh Hou ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Silicon Content ◽  
Volume Expansion ◽  
Active Material ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Clear Correlation ◽  
Graphite Composite ◽  
Thickness Change ◽  
Capacity Loss

Abstract One promising way of compensating for the repeated volume expansion and contraction of silicon as an anode active material in lithium ion batteries (LIBs) is to embed silicon within a graphite matrix. Silicon-graphite (SiG) composites combine the advantageous properties of graphite, i.e., large electrical conductivity and high structural stability, with the advantageous properties of silicon, i.e., high theoretical capacity. Graphite has a much lower volume expansion upon lithiation (≈ 10%) than pure silicon (≈ 300%) and provides a mechanically stable matrix. Herein, we present an investigation into the electrochemical performance and thickness change behavior of porous SiG anode compositions with silicon contents ranging from 0 wt% to 20 wt%. The electrode composites were studied using two methods: in situ dilatometry for the thickness change investigation and conventional coin cells for the assessment of electrochemical performance. The measurements show that the initial thickness change of SiG electrodes increased significantly with the silicon content, but it leveled off during cycling for all compositions. There appears to be a correlation between silicon content and capacity loss, but no clear correlation between thickness change and capacity loss rate was found.

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